The present invention relates to an oil separation device of an engine.
Conventionally, an oil separation device to separate oil mists contained in blow-by gas which generates in a crank chamber of an engine is known (see Japanese Patent Laid-Open Publication No. 2008-038620).
In this oil separation device, an oil separation chamber is provided in a space inside a cylinder head cover of the engine. In the oil separation chamber, a partition plate to partition this chamber into an upstream chamber and a downstream chamber is provided. This separation chamber has a connection hole to restrict flow of the gas passing through this hole and thereby increase the flowing speed of the gas. Further, a screen plate is provided downstream of the partition plate, facing the partition plate. The blow-by gas passing through the connection hole hits against the screen plate, so that the oil mists contained in the blow-by gas can be trapped at the screed plate.
The blow-by gas having hit against the screen plate (the gas flow after the oil mists are removed) flows down through a gas-passing through hole formed below the screen plate. Meanwhile, liquid oil which is formed after hitting of the oil mists against the screen plate naturally flows down along a gas-hitting face of the screen plate, drops into a concave oil-discharge portion which is formed below the gas-passing through hole, and is finally discharged to the outside of an oil circulation system. Thus, the oil mists contained in the blow-by gas can be separated.
According to the conventional oil separation device of an engine, however, since the oil trapped at the screen plate drops into the oil-discharge portion (oil pocket portion) through the gas-passing through hole which constitutes a gas-flow passage, part of the oil which is in the middle of dropping down is carried away by the gas flow passing through the gas-passing through hole, so that there is a problem in that the efficiency of oil trap may deteriorate.